1. Field of the Invention
Exemplary embodiments of the present invention relate to a method of driving a light source. More particularly, exemplary embodiments of the present invention relate to a method of driving a light source for enhancing display quality, a backlight apparatus for performing the method and a liquid crystal display apparatus having the backlight apparatus.
2. Description of the Related Art
Generally, a liquid crystal display (“LCD”) device typically includes an LCD panel that displays an image using the light transmittance characteristics of liquid crystal molecules, and a backlight assembly disposed below the LCD panel to provide the LCD panel with light.
The LCD panel typically includes an array substrate, an opposite substrate and a liquid crystal layer. The array substrate typically includes a plurality of signal lines, a plurality of thin-film transistors (“TFTs”) respectively connected to the plurality of signal lines and a plurality of pixel electrodes respectively connected to the plurality of TFTs. The opposite substrate faces the array substrate and has a common electrode. The liquid crystal layer is interposed between the array substrate and the opposite substrate. When an electric field is applied to the liquid crystal layer, the arrangement of liquid crystal molecules of the liquid crystal layer is altered to change light transmittance, so that an image is displayed. Here, when the light transmittance is increased to a maximum, the LCD panel may display a white image having high luminance. Alternatively, when the light transmittance is decreased to a minimum, the LCD panel may display a black image having relatively low luminance.
Moreover, in order to prevent the contrast ratio (“CR”) of an image from decreasing and to minimize power consumption, a local dimming driving method has recently been developed. In the local dimming driving method, a light source providing light to the LCD panel is divided into a plurality of light-emitting blocks. The light emitting blocks may be driven to control an amount of light displayed thereby in correspondence with the luminance of an image corresponding to the light-emitting blocks.
The local dimming driving method employed in a backlight typically includes a global dimming method, a one-dimensional (1-D) dimming method, a two-dimensional (2-D) dimming method, a three-way dimming method, a boosting method, or various other methods. The global dimming method (or, O-D dimming method) is a method in which the luminance of the display image is entirely adjusted, e.g., the entire backlight is dimmed or brightened according to a corresponding display image. The 1-D dimming method is that in which the luminance of the display image is adjusted by predetermined lines such as a horizontal line or a vertical line. The 2-D dimming method is that in which the luminance of the display image is partially adjusted in accordance with a position of the display image with respect to an x-axis and a y-axis. The 3-way dimming method is that in which a luminance image is dimmed by using position information and color information. The boosting method such as an adaptive luminance and power control (“ALPC”) is a method wherein a luminance image is increased so as to increase image quality.
However, since the local dimming driving method is a driving method in which driving is performed in blocks, flicker is generated due to subtitles in multimedia contents such as a movie. In particular, since an entire screen is dimmed or boosted by the global dimming method and the boosting method, flicker is generated due to a luminance difference between frames. Moreover, the number of blocks is small in the 1-D dimming method, so that a luminance difference between blocks may be undesirably perceived by a viewer within the same frame. Furthermore, in the 2-D dimming method, flicker is generated due to a luminance difference of blocks including subtitles.
In addition, when driving blocks are increased as a solution to the above in order to decrease the flicker due to the subtitles, the number of driving integrated circuits (“ICs”) is increased. Thus, a great number of driving blocks may not be used in the global dimming method or the 1-D dimming method, and the flicker due to the boosting method may not be prevented.